Since 2021, we have posted some extra difficult Sunday Stumpers, about once a month. These will be quite tough puzzles, but with a logical path to be found (and solution videos to help). This ninth Sunday Stumper of 2022 is a Slitherlink (Switch) puzzle by Matej Uher, author of our new Slitherlink and Variations 2 book. Each clue here has to switch with one of its orthogonal neighbors, so it will be quite a challenge to find the complete loop.

(view directly for a larger image)

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to switch between edgex mode where left click+drag draws lines and right click marks X’s, and a shading and number entry mode to mark/update the switched clues.)

Theme: Knight’s Moves

Author/Opus: This is the 5th puzzle from guest contributor Matej Uher.

Rules: Standard Slitherlink rules. Also, each given clue has to switch its initial position with one of its adjacent neighbors.

Also, see this example:

Difficulty: 5 stars

Time Standards (highlight to view): Grandmaster = 30:00, Master = 45:00, Expert = 1:30:00

Solution: PDF and solving video.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to switch between edgex mode where left click+drag draws lines and right click marks X’s, and a shading and number entry mode to mark/update the liar clues.)

Theme: Bull’s-Eye

Author/Opus: This is the 419th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Variation of Slitherlink rules. Exactly one clue in each row and column is incorrect and must represent another number.

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 8:45, Master = 13:30, Expert = 27:00

Solution: PDF and solving video.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

Theme: Columns

Author/Opus: This is the 11th puzzle from guest contributor Michael Tang.

Rules: Standard Slitherlink rules.

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 2:30, Master = 5:15, Expert = 10:30

Solution: PDF and solving video.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

Theme: Empty Middle

Author/Opus: This is the 231st puzzle from our contributing puzzlemaster Murat Can Tonta.

Rules: Standard Slitherlink rules, but any two consecutive line segments cannot have the same length (i.e., on both sides of any turn, the loop must travel different lengths).

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 2:30, Master = 5:00, Expert = 10:00

Solution: PDF and solving video.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

Theme: Pairs

Author/Opus: This is the 11th puzzle from guest contributor Eric Fox.

Rules: Standard Slitherlink rules.

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 1:30, Master = 2:00, Expert = 4:00

Solution: PDF and solving video.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

Theme: Antisymmetry

Author/Opus: This is the 383rd puzzle from our contributing puzzlemaster Grant Fikes.

Rules: Standard Slitherlink rules.

Difficulty: 2 stars

Time Standards (highlight to view): Grandmaster = 1:15, Master = 1:40, Expert = 3:20

Solution: PDF and solving video.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools in edgex mode where left click+drag draws lines and right click marks X’s)

Theme: 2×2

Author/Opus: This is the 98th puzzle from our contributing puzzlemaster Ashish Kumar.

Rules: Standard Slitherlink rules.

Difficulty: 1 star

Time Standards (highlight to view): Grandmaster = 0:30, Master = 0:45, Expert = 1:30

Solution: PDF and solving video.

Note: Follow this link for classic Slitherlink and this link for Slitherlink variations. If you are new to this puzzle type, here are our easiest Slitherlink puzzles to get started on. More Slitherlink puzzles can be found in The Art of Puzzles, Slitherlink and Variations, and our beginner-friendly book Logic Puzzles 101.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between number entry and shading modes.)

Theme: Mystery Box

Author/Opus: This is the 12th puzzle from guest contributor Sam Cappleman-Lynes.

Rules: Place a number from 0 to 9 into each area so that no two areas that touch orthogonally share the same number. Wherever four areas meet at a point (marked with dots as a visual aid), the numbers in those areas must add up to 10.

Also, see this example:

Difficulty: 4.5 stars

Time Standards (highlight to view): Grandmaster = 14:45, Master = 21:00, Expert = 42:00

Solution: PDF and solving video.

Note: Follow this link for other less common Number Placement puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Dominoes

Author/Opus: This is the 239th puzzle from our contributing puzzlemaster Prasanna Seshadri.

Rules: Place a number from 0 to 9 into each area so that no two areas that touch orthogonally share the same number. Wherever four areas meet at a point (marked with dots as a visual aid), the numbers in those areas must add up to 10.

Also, see this example:

Difficulty: 3.5 stars

Time Standards (highlight to view): Grandmaster = 4:45, Master = 7:00, Expert = 14:00

Solution: PDF and solving video.

Note: Follow this link for other less common Number Placement puzzles.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to shift between number entry and shading modes.)

Theme: Order and Disorder

Author/Opus: This is the 375th puzzle from our managing editor Serkan Yürekli.

Rules: Fill each row and column of the grid with the digits 1 to 5 and two blackened cells. Numbers outside the grid indicate the sum of the digits between the two blackened cells in that row or column. Blackened cells are allowed to touch. Or see here.

Difficulty: 3 stars

Time Standards (highlight to view): Grandmaster = 4:30, Master = 6:30, Expert = 13:00

Solution: PDF and solving video.

Note: Follow this link for other less common Number Placement puzzles.